The present invention relates to a fluid pump.
A prior art fluid pump 10 is shown in FIGS. 1-3. FIG. 1 illustrates the prior art fluid pump 10 which includes a solenoid 12, a spring 14, and a piston 16 within a cylinder 18. Intake and output valves 20, 22 are located on the cylinder 18 which pumps fluid (e.g., liquid and gas) out of the pump 10. During the compression stroke shown in FIG. 1, the solenoid 12 is de-energized and the spring 14 traverses the piston 16 in the direction of arrow 17. Fluid is forced out of the output valve 22. At the end of the compression stroke, the solenoid 12 is energized so as to overcome the force of the spring 14 and retract the piston 16 in the direction of arrow 19 as shown in FIG. 2. Retraction of the piston 16 enlarges the pumping chamber 24 and draws fluid into the pumping chamber 24 through the intake valve 20. No fluid flows out of the output valve 22 during the suction stroke. At the end of the suction stroke, as shown in FIG. 3, the spring 14 is compressed. When the solenoid 12 is de-energized, the spring 14 decompresses and initiates the compression stroke pumping fluid out of the output valve 22 as shown in FIG. 1. The cycle repeats to pump fluid out of the fluid pump.
The solenoid 12 is energized to effectuate the suction stroke and de-energized to allow the spring 14 to effectuate the compression stroke. This cycle is repeated to draw fluid into the pumping chamber 24 and pump fluid out of the fluid pump 10. For one half of the travel of the piston 16, namely, the suction stroke, no fluid is pumped out of the fluid pump 10. Fluid is only pumped out of the fluid pump 10 during the compression stroke. As a result, the fluid flow requirement of the fluid pump 10 must be designed into the compression stroke. If more fluid flow is desired then the stroke of the piston 16 must be increased or the area of the piston 16 must be enlarged to increase the linear volumetric displacement of the piston 16 during the compression stroke. Unfortunately, these adjustments produce large spikes in fluid pressure at the output valve 22 since fluid flows out of the fluid pump only during the compression stroke. Alternatively, to increase the fluid flow rate, the cycles per minute of the piston 16 may be increased. Unfortunately, this adjustment increases undesirable vibration and noise.
Accordingly, there is a need in the art for an improved fluid pump.